rt2x00: Remove usage of IEEE80211_CONF_CHANGE_BEACON_INTERVAL

IEEE80211_CONF_CHANGE_BEACON_INTERVAL was deprecated a month ago,
it is about time to remove all usage from the rt2x00 drivers and
use the correct beacon interval configuration through the bss_info
structure.

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2x00.h

@@ -417,6 +417,8 @@ struct rt2x00lib_erp {
 	short pifs;
 	short difs;
 	short eifs;
+
+	u16 beacon_int;
 };
 
 /*